Click the <Options><Processing Settings> menu (or press F4) and select the "Calibration" tab to access the calibration settings. You can also click the corresponding toolbar button to access these settings.
By default, the analyzer is calibrated to units of volts. The calibration options allow you to calibrate the analyzer to a wide range of engineering units.
Enable: if disabled the analyzer will be uncalibrated and the amplitude values will be in units of "Percent Full Scale" or "dB Full Scale" where 0 dB is the clipping point of the waveform. Calibration is enabled by default.
Calibration File: selects which calibration file to apply. The filenames "Volts" and "Millivolts" are reserved names and always available. Any user created calibration files will be added to this list.
File Edit/New: allows you to create or edit a calibration file.
There are two calibration methods:
1) Directly specify transducer sensitivity - select the transducer type and then enter its actual sensitivity. For example, 45 mV/PA for a microphone (consult your transducer calibration sheet for this information).
2) Calibrate to an external source - this allows you to calibrate to a known external reference. With this information we can conpute the correct scale factors. Here is the procedure:
Connect a steady state reference pure tone (such as a mic calibrator) to the input of the selected channel (do not use a DC level or noise signal).
Select the applicable units for the reference signal or select "Custom" and enter the axis labels to the right.
Enter the actual reference signal level value in the edit control (for example 94.0 dB SPL)
Select the reference signal type: "Peak", "RMS" or "Peak to Peak" as appropriate (mic calibrators produce RMS values)
Press the "Measure External Signal" button. The analyzer will then measure and display the voltage and frequency. Wait for it to stabilize. The analyzer will then compute the corresponding scale factors.
If you are calibrating to units of Acceleration the "Convert Acceleration To" field will activate and allow you optionally convert the spectrum to velocity or displacement. These conversions do not apply to the time series display.
You may customize the amplitude axis labels by directly modifying them in their respective edit boxes.
Channel Name: Enter a name for the channel - this is shown on all plots and utilities to help identify the signal.
See also: Scaling, Transducer Compensation Settings,